Japanese Patent Application Publication No. 2013-189128 discloses a pneumatic tire provided in the tread portion with: two shoulder circumferential main grooves; a center circumferential main groove disposed therebetween; a middle circumferential sub groove disposed between the center circumferential main groove and each shoulder circumferential main groove; axially inner crown lateral grooves disposed in a part between the center circumferential main groove and each of the middle circumferential sub grooves to divide this part into axially inner crown blocks; axially outer crown lateral grooves disposed in a part between each of the shoulder circumferential main grooves and the adjacent middle circumferential sub groove to divide this part into axially outer crown blocks; and shoulder lateral grooves disposed in a part between each of the shoulder circumferential main grooves and the tread edge to divide this part into shoulder blocks.
On both sides of each shoulder circumferential main groove, the axially outer open ends of the axially outer crown lateral grooves are respectively aligned with the axially inner open ends of the shoulder lateral grooves. Thereby, when running on snowy road, crisscross compacted snow is formed in the shoulder circumferential main groove, the axially outer crown lateral groove and the shoulder lateral groove.Such compacted snow provides a sharing force and helps to improve the snow performance of the tire.But, in the case of the disclosed tire, the crisscross compacted snow is difficult to provide a large sharing force against a lateral force generated for example during cornering for the following reasons.Since the axially outer open end of the axially outer crown lateral groove faces the axially inner open end of the shoulder lateral groove, the axially outer end of the compacted snow in the axially outer crown lateral groove and the axially inner end of the compacted snow in the shoulder lateral groove are not supported by groove walls and they support each other.Therefore, although the sharing force in the tire axial direction, of the compacted snow in the shoulder circumferential main groove makes a contribution to the sharing force against the lateral force during cornering, the sharing force in the tire axial direction, of the compacted snow in the axially outer crown lateral groove, and the sharing force in the tire axial direction, of the compacted snow in the shoulder lateral groove can not make a contribution thereto.As a result, it is difficult for the compacted snow to generate large lateral grip force, and the tire can not exert sufficient cornering performance on snow covered roads.Thus, there is room for improvement in the cornering performance on snow covered roads.